<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <!-- 页面的样式 -->
    <style>
        /* 重置样式，清楚浏览器自带的边框边距等 */
        * {
            /* 外边距 */
            margin: 0;
            /* 内边距 */
            padding: 0;
        }
        .big {
            background-color: gray;
        }

        p {
            font-size: 60px;
            color: red;
        }

        #p1 {
            font-style: italic;
        }

        .div1 {
            border: 1px solid red;
        }

        .a {
            color: aquamarine;
        }

        #ul li.li2 {
            list-style: none;
        }
        .li1,
        .li2,
        .li3,
        .li4 {
            color: red;
        }
    </style>
</head>

<body>
    <div class="big">
        <p id="p1">我是一段文字</p>
        <p id="p2">我是另外一段文字</p>
        <div class="div1 a">我是div</div>
        <div class="div1 b">我是div</div>
        <div class="div1 a">我是div</div>
        <div class="div1 b">我是div</div>
        <ul id="ul">
            <li class="li1">1</li>
            <li class="li2">2</li>
            <li class="li3">3</li>
            <li class="li4">4</li>
        </ul>
    </div>
</body>

</html>